影响血压的主要因素是（），（）。
参考答案：心排血量；外周阻力
It was _____ computer games that cost the young man a lot of precious time that he ought ____ on
his lessons.[ ]
A. to play, to be spending
B. playing, to spend
C. played, to have spent
D. playing, to have spent
寄存器R13除了可以做通用寄存器外，还可以做（）。
A、程序计数器
B、链接寄存器
C、栈指针寄存器
D、基址寄存器
